ICMCTF 2012! - CD-Lab Application Oriented Coating Development

EP-5 The effective Indenter concept applied to a comprehensive 3D
infinitesimal wear model, N. Bierwisch (n.bierwisch@siomec.de), N.
Schwarzer, Saxonian Institute of Surface Mechanics, Germany
A new sophisticated wear model has been developed on the basis of the
effective indenter concept [1, 2] by using the extended Hertzian approach
[3]. Fed properly from physically performed experiments like ordinary
Nanoindentation and lateral Nanoindentation via effective interaction
potentials the models do not only allow to analyze certain tribological
experiments like the well known pin-on disk test, but also to forward
simulate such tests and even give hints for better component life-time
predictions. The work will show a few examples.
[1] N. Schwarzer, G. M. Pharr: „On the evaluation of stresses during
nanoindentation with sharp indenters ”, Thin Solid Films, Vol.469-470C pp.
194-200
[2] N. Schwarzer, T. Chudoba, G. M. Pharr: „On the evaluation of stresses
for coated materials during nanoindentation with sharp indenters ”, Surf.
Coat. Technol, Vol 200/14-15 pp 4220-4226
[3] N. Schwarzer: "The extended Hertzian theory and its uses in analysing
indentation experiments", Phil. Mag. 86(33-35) 21 Nov - 11 Dec 2006 5153
– 5767, Special Issue: “Instrumented Indentation Testing in Materials
Research and Development”
EP-6 Mechanical Characterization of RF-DC Plasma Nitrided Tool
Steels, T. Aizawa (taizawa@sic.shibaura-it.ac.jp), Shibaura Institute of
Technology, Japan, Y. Sugita, YS Electric Industry, Co. Ltd., Japan
Pulse-enhanced plasma nitriding has been widely utilized as an industrial
surface treatment. Various types of steel parts and components with variety
of dimensional geometry are plasma-nitrided with high qualification in the
nitrided layers and with controllability of hardness profile; e.g. formation of
white layers is disliked in the nitrided tool steels. The present paper aims at
lower temperature nitriding; RF-DC plasma nitriding method is proposed to
describe the inner nitriding behavior of tool steels with comparison to the
conventional DC-plasma and pulse-enhanced plasma nitriding processes.
This new nitriding system works around 2 MHz with automatic matching;
RF and DC conditions are independently controlled and wide range of
pressure is also utilized for nitriding. First, SKD-11 substrate is employed to
investigate the effect of holding temperature, pressure and hydrogen to
nitrogen gas ratio on the surface hardness. After pre-sputtering for 900 s,
plasma nitriding is performed by RF (200 V) and DC (-500 V) for 7200 s at
753 K; the average hardness reaches to 1100 to 1300 in the dependent
manner on the RF-volt and pressure. Uniform nitriding takes place after
observation on the cross-sectional SEM and optical microstructure images.
Fine distribution of CrN with less population of iron nitrides in the nitrided
layer is responsible for relatively high hardness even by lower temperature
nitriding.
EP-7 Patterned Film Effects on the Adhesion of Al/TiN Barrier using
Fracture-Energy Based Finite Element Analysis, C.C. Lee
(changchunlee@cycu.edu.tw), Department of Mechanical Engineering,
Chung Yuan Christian University, Chungli, Taiwan, C. S. Wu, Department
of Mechanical Engineering, Chung Yuan Christian University, Taiwan, B.F.
Hsieh, S.T. Chang, Department of Electrical Engineering, National Chung
Hsing University, Taiwan
Currently, TiN films in the nanoscale order are widely used as barriers in
multi-level interconnect systems of semiconductor devices. However, when
an external loading or thermal stress is applied, the adhesion capability
between barriers and conductive metals increases the likelihood of the
interfacial delamination of dissimilar thin films, which is one of the
important reliability issues in advanced interconnect technology. To
quantify the adhesion of Al/TiN thin film, finite element analysis based on
the interfacial fracture theory is presented to estimate precisely the cracking
energy of the thin film. Through a comparison of four-point bending test
data with the predicted results, the proposed simulated methodology is
validated to be highly reliable in estimating the interfacial energy release
rate of Al/TiN stacked films. Furthermore, the analysis results also indicate
that the thickness and Young’s modulus of dielectrics within testing
samples both have a significant effect on the interfacial cracking energy of
Al/TiN thin film.
EP-8 Cyclic Creep and Fatigue Testing of Nanocrystalline Copper
Thin Films, Y.T. Wang, C.J. Tong, W.T. Tseng, M.T. Lin
(mingtlin@nchu.edu.tw), National Chung Hsing University, Taiwan
A microtensile testing for studying the cyclic fatigue mechanical properties
of freestanding nanocrystalline copper thin film with thickness of submicrometer
was performed to observe its mechanical response under
tension-tension fatigue experiments with a variety of stress amplitude and
mean stress conditions at cyclic loading frequencies up to 20 Hz. Tensile
sample loading was applied using a piezoelectric actuator. Loads were
measured using a capacitance gap sensor with a mechanical coupling to the
sample. The experiments were carried out with feedback to give load
control on sputter deposited 300, 500 and 700 nm Cu thin films. Loading
cycles to failure reached over 10^6 at low mean load with a trend of
decreasing cycles to failure with increasing mean load and load amplitude
as anticipated. The cyclic results provided clear evidence for a cyclic creep
rate dependent and change in failure mechanism from crack formation to
extended plasticity as the mean load and load amplitude are decreased.
Moreover, the length scale dependence on fatigue mechanism and cyclic
creep of tested films were observed.
EP-9 On the determination of coating toughness during
nanoindentation, J. Chen (Jinju.chen82@gmail.com), Newcastle
University, UK
The ceramic coatings have fulfilled a wide range of functions such as wear
resistance, energy storage, and optical properties. Due to their low fracture
toughness, however, they usually show complex crack characteristics when
these ceramic coatings are in contact with foreign objects. Such local cracks
can affect the integration of the entire component as well as the function of
the coatings. In order to optimise the material selection, design and
fabrication, it is essential to determine the fracture toughness.
Nanoindentation tests have been widely used to evaluate fracture toughness
of brittle materials. With decrease of the coating thickness and the
introduction of complex composition and structure, the fracture morphology
becomes more complicated. This increases the difficulty in determining
fracture toughness. For the thin coatings, energy based models have been
shown to be effective.
Based on determination of unloading curve at the start and end points of the
crack induced pop-in, one can assess fracture toughness. However, the
existing models give a loose bound of fracture toughness limits.
Therefore, an improved method has been proposed based on a refined
approach to determine the unloading curve at the start and end points of the
crack induced pop-in. The semi-analytical generalized expressions have
been presented to determine the fracture toughness of coatings for
nanoindentation tests performed under both load and displacement control.
This has provided a valuable theoretical guideline to determine fracture
toughness from the energy point of view. Furthermore, this approach has
been validated by nanoindentation tests on various coatings.
EP-10 Scratch Test of Optimized TiSiN Coating Deposited Via A
Combination of DC and RF Magnetron Sputtering, A.R.Bushroa. Abdul
Razak (bushroa@um.edu.my), University of Malaya, Malaysia, B. Beake,
Micro Materials Ltd, UK, M. Haji Hasan, University of Malaya, Malaysia,
M.R. Muhammad, Multimedia University, Malaysia
An optimized magnetron sputtered TiSiN coating on a high speed steel
substrate was fabricated using a combination of direct current (DC) and
radio frequency (RF) power in a physical vapor deposition (PVD)
technique. Controlled samples were also developed for a comparison,
whereby the DC power was varied at 300 and 400 W. The optimized
sample was coated at 500 W. A scratch test was performed to investigate
wear resistant of the coating. The test was done with at least nine constant
load wear cycles on the coating. The coating deposited with DC power of
300 and 400 W failed after 4 th and 6 th cycles, but the coating of 500 W
resisted wear even after 9 th cycle. This result was supported with the optical
image of scratch track, whereby no evidence of chipping, delamination and
total exposure of substrate were observed. Mechanical property of
optimized coating was also investigated for tribological performance. The
value of effective ratio of hardness to relative modulus (H/Er*) was
discussed to relate with the wear resistance. Furthermore, failure mode of 3
distinguished stages of deposited coating was explored.
EP-11 Evaluation of Adhesion of TiAlN/CrN Multilayer Coatings
Deposited by CFUBMS, H. ÇİÇEK (hikmetcicek25@hotmail.com),
Ataturk University, Turkey, Ç. Laloğlu, Turkey, Ö. Baran, Erzincan
University, Turkey, E. Demirci, V. EZİRMİK, İ. EFEOĞLU, Ataturk
University, Turkey
TiAlN/CrN multilayer films widely used to increase the life of the materials
in industry especially cutting tools and machine parts which work high
velocity and dry friction conditions. One of the important factors affecting
the performance of coatings is the adhesion of film to the substrate. This
work, TiAlN/CrN films were coated on M2 tool steels by CFUBMS
according to the taguchi technique. Microstructurel and mechanical
properties of these films were characterized by X-ray diffraction, SEM and
micro hardness tester. And adhesion properties of these films determined by
scratch tester. The obtained results from the adhesion test evaluated with
hardness, thickness and structure of the films.
113 Thursday Afternoon Poster Sessions